Method of hermetically sealing the inner wall of a refractory air bell



P. KUCERA Filed July 23, 1938 fmveao P9237 'K man,

y o eggs Feb. 4, 1941.

METHOD OF HERDIIIETICALLY SEALING THE INNER WALL OF A REFRACTORYv AIR BELL Patented Feb. 4, 'i941 PATENT f OFFICE 2,230,597 METHOD F HERMETICALLY SEALING THE INNER WALL BELL 0F A REFRACTORY AIR i Peter Kucera, Allison Parli, Pa., assigner t'o Hart..

. ford-Empire Company, Hartford, Conn., a corporation of Delaware Application July 423, 1938, Serial No. 220,900

3 Claims.

This invention relates to thefeeding of molten glass in mold charges of predetermined weight and shape by the use of a pneumaticfeeder as, for example, that of the type disclosed in Patent No. 1,997,799, granted to me as assignor to Hartford-Empire Company, Hartford, Connecticut. t

A pneumatic glass feeder of the type above referred to comprises a glass feeding lforehearth or container having an outlet in its bottom and a refractory bell supported in the feeding container above and in axial alignment with the outlet. The bottom or rim portion of the bell is continuously submerged by glass of the supply body in the container and a. space normally exists in the bell above the glass therein for the applicatlon to such glass of periodic super-,atmose pheric and sub-atmospheric impulses by which discharge of glass through the outlet is periodically accelerated and periodically retarded or halted. Y A feeder of this type may have the air bell supported in the feeding container in the position described through the instrumentality of a hollow metallic shank which ts into the upper portion or stem of the air bell and aords support therefor. l

The refractory walls of an air bell of the character described are. suiilciently porous to allow comings or faults of air bells of` the character described.

A further object of the invention is to provide a simple, reliable and eicient method of hermetically sealing the innerwall of the cavity of a refractory air bell of the character described, including the surfaces at its juncturev with a metallic supportingv shank while permitting free ingress and egress of air to and from the cavity of the-bell through a passage in .the metallic supporting shank. 1

Other objects and advantages ofr the inventionlwill. hereinafter become apparent or will be pointed out in the following description of the (Cl. -49-77) l I manner of applying the invention to an air bell assembly in the feeding forehearth or container of the present invention to hermetically seal thel inner wall of the airl bell cavity, andl Fig. 2 is a vertical sectional view showing the air bell assembly and a portion of the forehearth or feeding container, together with molten glass completely lling the cavity of the air bell as eected by a step of the method of the present invention, and showing also by a dot-and-dash line the maximum height to which glasswill subsequently .be drawn upwardly in the cavity of the air-bell during normal glass feeding operations. In the drawing, a glass feeding container Ill y has` a discharge outlet Il (Fig. 1) in its bottom. The showing of the container and of its outlet is largely diagrammatic, as these parts may be of any suitable shape and construction. .In general, the structure shown represents the outer end portion of a glass feeding 4forehearth to which molten glass passes continuously from a melting tank (not shown), so that a supply body of molten glass continuously fills the 'feeding ntainer to a'level such as that indicated at I2.A

The top or cover portion of the container, designated I 0a, is provided with a suitable opening I3, through which extends the neck or stem portion Il of a refractory air bell I5. The air bell I 5 is supported in position to depend into the molten glass in the feeding container, usually in axial alignment with the outlet, so that glass normally lseals the lower end of the air bell and iills a substantial portion of theicavity therein.

As shown, the cavltyfffl of the air bell is merged into a central bore I'I of reduced diameter extending through the stem or neck portion of the refractory bell member, so as to provide a downwardly facing shoulder I8 at the upper end of the air bell cavity.- A metallic hollow shank I9 extends through the bore Il of the stem or neck portion of the refractory bell, and has an enlarged lowerend portion or headfitting closely in the upper portion of the cavity of the air bell against shoulder I8.

A cap 2l on the upper end of the stem of 'the air bell surrounds the protruding portion of the shank I9, and nuts 42 and 23 are threaded on such shank against the cap 2| tov connect the shank I9 firmly, although detachably, with the refractory bell. The arrangement is such that the refractory air bell may be supported within the feeding container at a predetermined desirable distance above the outlet II by attaching the shank I9 to any suitable supporting means (not shown). Also, the bore -of the shank, indicated at 24, is adapted to be, and in practice is, suitably connected with any suitable source 'of supply of super-atmospheric and sub-atmospheric pressures, such as the air rarefying and compressing device shown in Patent No. 1,997,799. 'I'his bore 24 in the metallic shank I9 is too small in cross-sectional area for molten glass to enter and pass upwardly therein.

The arrangement describedY is subject to the disadvantages hereinbefore mentioned in that air may filter through the refractory walls of the cavity of the air bell above the glass therein, and also may pass through the joint between the metallic shank I9 and the surrounding stem or neck portion of the air bell. While this passage of air may be of small volume, it necessarily is uncontrolled and therefore interferes with the attainment of an accurate control of the desired pressures on the glass in the air bell cavity, and hence tends to prevent desirable control of the weight of the successive charges which in practice are obtained by regularly timed operations of severing mechanism (not shown) which severs glass charges from successive mold charge masses of glass in suspension from the outlet of the feeding container.

Tb obviate this disadvantage the prsent invention proposes to provide a glaze or molten glass seal for the inner wall of the'refr-actory air bell above the level to which glass rises in the air bell during normal feeding operations and for the joint between the metallic shank I! and the refractory air bell. To effect this brought to predetermined temperature and condition of viscosity before the commencement of glass feeding operations, after the air bell has been disposed within the feeding container substantially as shown in,Fig.` 1. This temperature and viscosity may be those appropriate for the feeding operations intended, or in some instances' the glass may be heated to a higher temperature before the glass feeding operations for the carrying out of the present invention.

After the glass is at the temperature and has the viscosity desired, an abnormal sub-atmospheric pressure is produced in the cavity oi' the air bell to cause molten glass to rise therein completely to the top of such cavity, and against the metallic shank Il, as to the level indicated at 2$,.in Fig. 2.y As aforesaid, the bore 24 of `the shank I9 is too small for the molten glass to enter'it. The molten glass thuswill be forced intimately into contact with all portions of the inner wall of the refractory air bell below the level of the small passage 24 and against the lower surface of the head 20 of the metallic shank I9 at the joint between it and the refractory air bell. The abnormal subatmospheric pressure referred to then is relieved, so that the lglass will fall to a 'lower level, as to the level further regulation thereof is required to produce the conditions desired, and feeding operations Thereafter the temperavture and viscosity of the glass are regulated, if

may be commenced, making `use of normal periodic super-atmospheric and sub-atmospheric pressures.

'During such norm-al feeding operations, the maximum or highest level to which glass will be drawn by sub-atmospheric pressure on the glass in the air bell cavity may be represented by the dot-and-dash line 26 in Fig. 2.

It will be clear from the foregoing description that the preliminary application of molten glass to the wall of the portion of the air bell cavity that norma1ly is located above the glass level will cause this wall to be coated with molten glass or glaze, thus producing a hermetic seal at the inner surfaces of this portion of the air bell cavity and at the joint between the metallic shank I9 and the refractory air bell. Since this portion of the air bell assembly is within the Vfeeding container .in a zone of high temperatures, such glass as may have been raised to position to cover and-temporarily seal the lower end of the small passage 24 in the metallic shank I9 will be sufiiciently molten or plastic to be blown therefrom when super-atmospheric pressure has been applied thereto after the relief of the abnormal sub-atmospheric pressure referred to. Thereafter, this passage 24 will be in open communication with the space above the glass in the air bell, and the super-atmospheric and sub-atmospheric impulses may be applied to such glass at the times determined by the operations of the timer of the feeding apparatus.

Uncontrolled passage of air through the refractory walls of the air bell and at the joint between the metallic shank and the air bell will thus be prevented and the periodically varied pressures on the glass in the air bell may be regulated to regulate and control accurately the weight of the charges obtained by the use of the glass feeding apparatus. The invention is susceptible of use to hermetically seal various surfaces other than that specifically described in the foregoing specification.

What I claim is:

1-. The method of hermencauy sealing the' inner wall of an air bell of a pneumatic glass feeder, comprising the steps of disposing the air bell in its operative position so that the bottom or rim portion of the bell is below the surface of a supply body of molten glass in a feeding container of the feeder and the upper portion of the cavity of the bell is above the highest level to which glass rises inthe cavity of such bell during normal operations of such feeder, apply, ing a sub-atmospheric pressure to the glass in said vbell sufficiently low to cause molten glass of the supply body to rise in the cavity of the bell to a height sufilcient to apply molten glass to the entire inner surface of said air bell, and thereafter relieving said sub-atmospheric pressure.

2. The method of hermetlcally sealing the inner wall of an air bell of a pneumatic glass feeder, said air bell having a passage of small cross sectional area at its-*top for applying pneumatic pressures to the cavity of said bell, comprising the steps of disposing said bell in operative position in a glass feeding container of the feeder so that the bottom or rim portion of the bell is below the surface of a supply body of molten glass in the container 'and the upper portion of the cavity of the bell is located above the highest level to which glass will rise therein during normal operations of such feeder and in a zone of high temperature, heating the glass estadista of the supply body at the bottom of said bell to a sufficiently high temperatureto cause it to coat l the inner surface of the bell when applied thereto, applying a sub-atmospheric pressure to the glass in the cavity of said bell sumciently low to cause said glass to rise completely to the top' of said cavity against the entire inner wall surface thereof, relieving said pressure, and apply- Y in a glass feeding container of the feeder so ing a positive pressure to said passage of small cross-sectional area to free the lower end thereof from any molten glass that might otherwise obstruct the same.

3. The method of hermetically sealing the inner wall of a refractory air bell of a pneumaticv feeder, said air bell having Aa metallic supporting.

shank joined to the refractory bell at the top of the cavity of the bell, said shank having a bore of small cross-sectional area for applying pneumatic. pressures to the cavity 'of said bell, comprising the steps of disposing the assembled bell and shank as a unit in operative position that the bottom or rim portion of .the bell is below the surface 'ofa supply body of moltenv glass in the container and the wall' of the upper portion lof the cavity. 4including the. joint between said metallic shank and the refractory 5 belris located above the highest level to which` glass will rise in said cavity' during normal. operations of the feeder and i n a zone of high temperature, heating the glass at the bottom of the bell to a suill'ciently--hish temperature t'o 10 

